Iodine is required for adequate thyroid hormone production, which is essential for brain development, particularly in the first trimester of pregnancy. Milk is the principal source of iodine in UK diets, and while small studies in Europe have shown organic milk to have a lower iodine concentration than conventional milk, no such study has been conducted in Britain. In view of the increasing popularity of organic milk in the UK, we aimed to compare the iodine concentration of retail organic and conventional milk and to evaluate regional influences in iodine levels. Samples of organic milk (n 92) and conventional milk (n 80), purchased from retail outlets in sixteen areas of the UK (southern England, Wales and Northern Ireland), were analysed for iodine using inductively coupled plasma MS. The region of origin of the milk was determined from information on the label. Organic milk was 42·1 % lower in iodine content than conventional milk (median iodine concentration 144·5 v. 249·5 ng/g; P < 0·001). There was no difference in the iodine concentration of either conventional or organic milk by area of purchase. However, a difference was seen in iodine concentration of organic milk by region of origin (P < 0·001). The lower iodine concentration of organic milk has public-health implications, particularly in view of emerging evidence of iodine deficiency in UK population sub-groups, including pregnant women. Individuals who choose organic milk should be aware that their iodine intake may be compromised and should ensure adequate iodine intake from alternative sources.

The study uses the 2005 Nielsen Homescan panel data to estimate price premiums and discounts associated with product attributes, market factors, and consumer characteristics, focusing on the organic attribute for five major fresh fruits and five major fresh vegetables in the United States. The results suggest that the organic attribute commands a significant price premium, which varies greatly from 13 cents per pound for bananas to 86 cents per pound for strawberries among fresh fruits and from 13 cents per pound for onions to 50 cents per pound for peppers among fresh vegetables. In terms of percentages, the estimated organic price premiums vary from 20% above prices paid for conventional grapes to 42% for strawberries among fresh fruits and from 15% above prices paid for conventional carrots and tomatoes to 60% for potatoes. Furthermore, prices paid for fresh produce are found to vary by other product attributes, market factors, and household characteristics.

The market value for organically grown produce in California was estimated to be at least 54 to 68 million dollars at wholesale prices in 1987. This market is rapidly growing. A 41 percent increase in the value of organically grown produce was observed in 1987. When this analysis was completed in early 1988, it was estimated that the wholesale value of the market could exceed $300 million by 1992. A sample analysis of 1986–1987 price and volume for organically grown broccoli showed relatively steady prices and a volume increase of over 50 percent, indicating a similar growth in market demand. Prices for organically grown produce are significantly higher than for conventional produce; however, in spite of high weekly volume volatility, organic prices appear to be less volatile than prices for conventional produce. This paper proposes that the collection, reporting, and analysis of organic produce market data be continued and improved and that new sources of data be integrated to ensure continued availability of timely market information. Availability of more market information should increase efficiency and aid the development of the organic produce industry. The paper also proposes that overall trends in the organic produce industry be systematically monitored by Federal-State Market News and that the increased use of market information by organic growers, growers considering the transition, and other interested parties in the industry be promoted.